The product has attracted some controversy owing to alleged adverse events and questions as to whether it is effective against the inhalational form of anthrax.

[7] The antigen (immunologically active) portions are produced from culture filtrates of a toxigenic, but avirulent, nonencapsulated mutant — known as V770-NP1-R — of the B. anthracis Vollum strain.

The study field sites were four wool-sorting mills in the northeastern United States where employees were sometimes exposed to anthrax spores in the course of their work.

Meanwhile, MBPI fell afoul of FDA inspectors and reviewers when it failed inspections (1993, 1997) and received warning letters (1995) and Notices of Intention to Revoke (1997) from the agency.

This program, initiated by the Clinton administration and announced by Secretary of Defense William Cohen in 1997, made the vaccine mandatory for active duty US service personnel.

The same year, a particularly damning FDA report was issued resulting in the temporary suspension of anthrax vaccine adsorbed shipments from the production plant.

Much controversy ensued due to the FDA infractions, the mandatory nature of the program, and to a public perception that anthrax vaccine adsorbed was unsafe — possibly causing sometimes serious side effects — and might be contributing to the highly politically charged malady known as "Gulf War syndrome".

Only 0.3% reported >1 day lost from work; 0.5% consulted a clinic for evaluation; and one person (0.02%) required hospitalization for an injection site reaction.

A second study, also between 1998 and 2000, at Tripler Army Medical Center, Hawaii, assessed adverse events among 603 military health-care workers.

In October 2000, a committee of the Institute of Medicine (IOM) of the National Academy of Sciences was asked by the US Congress to review anthrax vaccine adsorbed according to the best available evidence.

With regard to safety, "The committee found no evidence that people face an increased risk of experiencing life-threatening or permanently disabling adverse events immediately after receiving anthrax vaccine adsorbed, when compared with the general population.

Nor did it find any convincing evidence that people face elevated risk of developing adverse health effects over the longer term, although data are limited in this regard (as they are for all vaccines)."

Owing to the controversy surrounding the administration of the vaccine to military personnel, however, some 6,000 US Postal Service employees balked at this, preferring to take their chances with the risks of residual anthrax spores in the workplace.

Despite the positive IOM assessment, mandatory vaccinations of military personnel were halted due to an injunction which was put into place on 27 October 2004.

The injunction cast questions about numerous substantive challenges regarding the anthrax vaccine in footnote #10,[21] yet the procedural findings centered on FDA procedural issues, stating that additional public comment should have been sought before the FDA issued its Final Rule declaring the vaccine safe and effective on 30 December 2003.

In that rulemaking the FDA published, but never finalized, a licensing rule for the anthrax vaccine in the Federal Register, which included an expert review panel's findings.

[24] After reviewing the extensive scientific evidence and carefully considering comments from the public, the FDA again determined that the vaccine is appropriately licensed for the prevention of anthrax, regardless of the route of exposure.

Also in 2005, the George W. Bush administration established a policy to ensure that the Strategic National Stockpile retains a current unexpired inventory of 60 million doses of anthrax vaccine adsorbed.

The reinstated policy required vaccinations for most military units and civilian contractors assigned to homeland bioterrorism defense or deployed in Iraq, Afghanistan or South Korea.

[25] A modification of previous policy allowed military personnel no longer deployed to higher threat areas to receive follow up doses and booster shots on a voluntary basis.

In February 2009, Emergent BioSolutions announced that the Drugs Controller General of India (DGCI) had approved licensing of Biothrax for distribution by Biological E. of Hyderabad.

[28] Emergent worked with the Biomedical Advanced Research and Development Authority (BARDA) within the Office of the Assistant Secretary for Preparedness and Response in the United States Department of Health and Human Services on the project.

[18] The approved FDA package insert for anthrax vaccine adsorbed contains the following notice: "The most common (>10%) local (injection-site) adverse reactions observed in clinical studies were tenderness, pain, erythema and arm motion limitation.

[32] The approved US FDA package insert for anthrax vaccine adsorbed contains the following notice: Immunosuppressive therapies may diminish the immune response to Biothrax.

The academy considered more than a dozen studies using various scientific designs, and heard personally from many concerned US military service members.

[19] While effective in protecting against anthrax, the licensed vaccine schedule is not very efficient, involving a cumbersome five (previously six) dose injection series.

On 19 December 2006, HHS voided the contract, because of stability problems with the vaccine, and a failure to start a Phase 2 clinical trial on time.

[34] In May 2008, Emergent Biosolutions, the Maryland-based successor to BioPort, both controlled by former Lebanese banker Faud el Hibri, acquired rights to Vaxgen's patents and processes.

[35] In October 2012, the US National Institute of Allergy and Infectious Diseases agreed to provide $6.5 million to the United Kingdom's Health Protection Agency for initial work on a potential future anthrax vaccine that could be delivered through the nasal passage instead of via a needle.

[36][37][38] The primary immunogen of acellular existing vaccines, i.e., Protective Antigen (PA), is highly thermolabile due to inherent structural and chemical instability.